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Births and Burials - Heortling population numbers crunched


Joerg

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With half the clan consisting of underage children, one has to inflict quite a death toll to keep population numbers stable. On average, a bit over half the children would survive to become adult. Doing the math for a steady state takes a bit.

With an average age of iniitation of say 16 years we can group the children in four age groups. Age up to four can be considered 80% survival, age group 5 to 8 70% survival, age group 9 to 12 60% survival and age group 13-16 50% survival.

With 50 births a year, that corresponds to 160 toddlers up to age 4, 140 children 5-8, 120 children 9-12 and 100 children 13-16, about to be initiated. On average, that's 30 initiations per year (taking into account that there will be a number of adults in the 13-16 range, and that mortality at that age may be lower) in a clan with 1040 people (adding up the number of children and doubling the result), and 30 deaths of adults, to keep the numbers stable.

When times have been hard, mortality goes up, and the children-to-adults ratio will rise, even when initiation age gets lowered. Population numbers will go down for half a generation while the birth rate increases, but my child mortality numbers above already take into account occasional famine and plague. The child mortality rates probably are too high with only a 10% mortality rate for the adults.

Let's drop the 13-16 age range from the number of children. That's an average of 40 children initiated per year in a clan of 840 people, and as many deaths of adults, still a 10% death rate.

Using the same survival rates with 80 children born in a year:

256 children age 1-4, 224 children age 5-8, 192 children age 9-12, 48 initiations per year on average. Total people in the clan 672*2 = 1344, on the high end of clan size, and a 14% death rate of adults of all ages.

Numbers of dead children in 4 years: age 0-4 64, age 5-8 32, age 9-12 32 - a total of 128, meaning 32 dead children per year to accompany the 48 adults - up to 80 funerals in the clan, same number as the births, so the numbers check out. Since the deaths will occur in times of hardship, probably less than half the number of funerals.

Let's try lower child mortality, 60 births a year, children defined as under 13.

age 1-4: 210 (30 deaths in 4 years, one child out of eight)
age 5-8: 190 (20 deaths in 4 years, one child out of ten)
age 9-12: 180 (10 deaths in 4 years, one child out of 18) - 60 deaths in four years, or 15 deaths per year.

On average 45 initiations per year, and as many adult deaths, in a clan of 960 people. Even less than 10% of the adults.

60 births a year means about 180 fertile mothers and as many fathers out of 480 adults. That leaves 120 non-reproductive adults, or a higher average birth frequency. It also means that there is a moderately high likelihood that a young woman leaving the clan above age 17 will leave a (usually welcome) child behind in her parental household, or take it along for adoption.

Widows leaving the clan should equal widows returning to the clan, and daugthers married out of the clan should equal daughters-in-law received, in a steady state situation. Widows remaining in the clan may still reproduce, with or without re-marrying inside the clan.

 

These numbers might need some attrition for people leaving the clan without dying, possibly taking along a few toddlers if moving to a city, joining the household of some tribal noble, or being taken into slavery, but that will just re-define the death figures.

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Telling how it is excessive verbis

 

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Y'all are neglecting Ernalda's blessings :) . Pregnancy rates can be higher, and perinatal mortality of mother and child (or children - multiple births are an option) reduced by Rune Magic. 180 fertile mothers could produce 90 (or even 180) live births per year, or you only need 120 (or even 60) mothers. At least in the latest incarnation of 'how Rune Magic works' (RQG)... There are plenty of people able to cast the right spells.

Now I'm sure many mothers would want to spread their births out a bit more than every year or two, but would 'duty to clan' following times of loss encourage more to group their pregnancies more tightly (or have 'just one more')? I gather the Romans had awards for mothers bearing 5 or more children.

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15 hours ago, Joerg said:

On average 45 initiations per year, and as many adult deaths, in a clan of 960 people. Even less than 10% of the adults.

Even split by gender that feels like a hard ceiling on the number of initiates the 1% godi can actively monitor through the process, especially for the boys who all come in together in a single annual clump.

Perversely the baby booms are more dangerous because with attention divided across more tweens you get more chances to flub a worship or spirit sense roll and end up inadvertently making a flawed human or botching the entire batch.

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8 hours ago, womble said:

Y'all are neglecting Ernalda's blessings :) . Pregnancy rates can be higher, and perinatal mortality of mother and child (or children - multiple births are an option) reduced by Rune Magic. 180 fertile mothers could produce 90 (or even 180) live births per year, or you only need 120 (or even 60) mothers.

Yes. I think I said so..

8 hours ago, womble said:

At least in the latest incarnation of 'how Rune Magic works' (RQG)... There are plenty of people able to cast the right spells.

However, there seems to be something like a fluctuating steady state in population, with population maxing out somewhere near sustainable maximum (which is 180k to 200k for Sartar, I suppose).

With each woman having 4 or 5 surviving kids, the population would explode. My calculations were based on the assumption that the clan population of 50% will more or less reflect a steady state, and that requires some child mortality, to whichever factors.

Without child mortality, making a cut at 12 years, you need clan population divided by 24 births per year, nnd for a steady state population, as many adult deaths. Making the cut at age 15, it's clan population divided by 30.

I'll have to check with an expert on Bronze and Iron Age graveyard populations, but I think my suggested attrition isn't too far from historical conditions.

8 hours ago, womble said:

Now I'm sure many mothers would want to spread their births out a bit more than every year or two, but would 'duty to clan' following times of loss encourage more to group their pregnancies more tightly (or have 'just one more')? I gather the Romans had awards for mothers bearing 5 or more children.

So had other regimes bent on racial purity.

Parent status is enough of a deal that the Orlanthi have an ersatz-ritual, the Wanderlore quests.

8 hours ago, jeffjerwin said:

Women are likely to use contraception, as much as fertility enhancements. Pregnancy isn't very convenient or comfortable no matter the magic, and Ernalda asks that her initiates be mothers, not brood hens.

There is a lot of status for a pregnant woman. Fertility magics get boosted (and reflect well on the unborn child, too). Having a breastfeeding baby on the arm is similar.

Contraception charms and fertility charms probably exist, and might even out in the statistic.

6 hours ago, scott-martin said:

Even split by gender that feels like a hard ceiling on the number of initiates the 1% godi can actively monitor through the process, especially for the boys who all come in together in a single annual clump.

But that job would be distributed between the godi and the elders - in fact, this is one job which the elders are best qualified to do.

 

6 hours ago, scott-martin said:

Perversely the baby booms are more dangerous because with attention divided across more tweens you get more chances to flub a worship or spirit sense roll and end up inadvertently making a flawed human or botching the entire batch.

This sounds like the Murphy's Rules self-beheading quota projected on initiations.

And we are talking about Orlanthi. Flawed humans are well within expectations when each and every magic went exactly right.

Telling how it is excessive verbis

 

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You might like to try a bigger picture number crunch:

http://www.metamorphosisalpha.com/ias/population.php

change the dates to Glorantha ones

put in initial pop number from the guide

alter the growth rate to get the current pop.

Glorantha's growth rate is much lower than earth's

you might want to do it in sections to compensate for things like the dragonkill

Births and deaths even out - after war more births. Magic is the same.

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Not sure about Glorantha, but there are a number of groups in the RW that practice celibacy after parturition, partly to avoid overpopulation, partly to protect the health of the woman - although it's of course expressed in mythical and allegorical terms. A fairly common practice is celibacy until the most recent baby is (at least partly) weaned, so anywhere between 6-24 months, with 12-18 months being a nice middle ground.

Having several sisters who've all been pregnant multiple times and had to care for both baby and toddler - I'd personally prefer thinking that Gloranthan women get a breather too, especially if we consider a lowered rate of infant and child mortality due to magic. Aunts, grandmothers, wetnurses and thralls are all well and good, but that stuff is rough no matter the circumstances.

There are also several cultures that promote a lot of intercourse during pregnancy to help the development of the child, but that's neither here nor there.

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4 hours ago, David Scott said:

You might like to try a bigger picture number crunch:

http://www.metamorphosisalpha.com/ias/population.php

The Heortling Stead Project produced a spreadsheet to help with this. I have a copy but I can't find a web source for it anymore (I think the yahoo group for it is gone) and I don't want to share as it's not mine. I am not sure if anyone remembers who put it together (Nick Brooke?) but if you can find them they might be willing to upload here.

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4 hours ago, Sir_Godspeed said:

Having several sisters who've all been pregnant multiple times and had to care for both baby and toddler - I'd personally prefer thinking that Gloranthan women get a breather too, especially if we consider a lowered rate of infant and child mortality due to magic. Aunts, grandmothers, wetnurses and thralls are all well and good, but that stuff is rough no matter the circumstances.

Toddlers are halfway out of the mother's responsibility unless she is the main nanny of the household (or even stead). Older sisters near initiation (from either side) are going to be assistant toddler keepers.

The core family of father mother full siblings is rarely the reality. It is pretty common for at least one parent to be absent. It is pretty common to have patchwork families, although only the children of one of the parents at the abode of the clan. First cousins and uncles, aunts, nieces and nephews within the same age bracket will grow up as siblings. If there are more households on the stead/in the townhouse enclosure, the children of the other households will grow up like cousins to the sibling group mentioned above.

Children of renowned god-talkers or of companions of tribal nobles are likely to see their parent(s) only on rare visits, and more likely to regard their grandparents or an uncle or aunt as their primary adult relationship.

All of that is of course a matter of social standing. Cottar households will have fewer folk to fall back to, and might be forced to step their births further apart.

Telling how it is excessive verbis

 

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22 hours ago, Joerg said:

The core family of father mother full siblings is rarely the reality.

Trust me, I know.

EDIT: It's been pointed out to me that this response was overly defensive and snide (my description, not theirs). I apologize, I was in an overall bad mood that day, and it colored how I read the above message.

Edited by Sir_Godspeed
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  • 4 weeks later...
On 9/18/2018 at 5:40 AM, womble said:

I gather the Romans had awards for mothers bearing 5 or more children.

Mussolini reinstated similar policies.  Here is a link to an article for those who can be bothered:

https://anthrosource.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1556-5823.2010.00002.x

Edited by Darius West
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On 9/18/2018 at 6:52 AM, jeffjerwin said:

Women are likely to use contraception, as much as fertility enhancements. Pregnancy isn't very convenient or comfortable no matter the magic, and Ernalda asks that her initiates be mothers, not brood hens.

Actually, this raises the issue of what the women of Genertela use as their primary method of birth control.  The real world example we have from records of the Roman Empire was a now-extinct variant of the genus Silphium https://en.wikipedia.org/wiki/Silphium.  In Glorantha, I have read in fan material that the henna equivalent used by Vingans acts as a contraceptive (and not just because it makes them look like gingers (jk)).  It is also quite possible to use a spirit with a disruption spell to target a fetus by its spirit in utero thus procuring an abortion (this is about the only way of safely removing a broo baby btw).  Now in the ancient world, trade in the silphium healing herb (it had uses beyond contraception) was big business, and there is no reason why it wouldn't be an important trade commodity in Glorantha as well, especially if it grows better in some specified climates (such as mountainous regions).  Has anyone else read of variant methods of contraception in Glorantha?  Certainly it is hard to have a female population who aren't utterly under the thumb without some measure of birth control, and hence it would be especially important in Esrolia I figure.

Edited by Darius West
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43 minutes ago, Darius West said:

Actually, this raises the issue of what the women of Genertela use as their primary method of birth control. 

As usual, I expect the Aldryami to discreetly sell humans any amount of contraceptives they want. Maybe other plants can be, er, inadvertently contraceptive, sterilizing or defect inducing as well.

Edited by The God Learner
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